RTL SDR As A Spectrum Analyzer

November 19, 2014 by Brian Benchoff 24 Comments

RTL-SDR, the USB TV tuner turned software-defined radio is an amazing device, capable of listening to nearly anything from 25MHz to 1750MHz, fits in your pocket, and costs about $20. Even more astonishing is that it’s also a kinda-okay spectrum analyzer. [Kerry D. Wong] tested out one of these USB TV tuner, and the results are exactly what you would expect: it lacks a little precision, and sampling bandwidth is only a tiny bit terrible, but it does work.

A stock USB TV tuner doesn’t come with a connector that would normally be used for spectrum analysis. A BNC connector can be easily attached, as can a terminator to match the 75Ω impedance of the SDR. This isn’t really necessary; the frequencies being measured are low enough that you can get away without one.

As far as software goes, [Kerry] first pulled out the usual suspects of the SDR world; rtlsdr-scanner distorted the measured spectrum, as did a lot of other SDR receivers. Gqrx SDR was the first one that worked well, but the king of this repurposing of USB TV tuners was OSMOCOM. There’s a huge number of tools for spectrum analysis right out of the box with this package.

How did the RTL SDR fare as a spectrum analyzer? Feeding some stuff in from a signal generator, [Kerry] discovered the LO in the RTL SDR was off by a hair. Also, OSMOCOM only measures amplitude in dB, not the dBm found in every other spectrum analyzer ever made. By measuring a 0 dBm signal whatever value displayed can be shifted up or down.

So, does it work? Yes, it does. If, for some reason, you need a spectrum analyzer now, can you use this? Yep. Pretty cool.

How To Get 50 More Zed From Your Rigol DS1054Z

November 12, 2014 by Kristina Panos 98 Comments

[Chris] has been spending a lot of time in the wife’s sewing room lately, and things got pretty serious late last night as he hacked his shiny new Rigol DS1054Z to unlock the 1104Z capabilities lurking within.

The rumors are true, and ungoverning the software is as simple as looking up your serial number and knowing the right URL for generating a valid license. [Chris] ran into a dud site, but that’s the price of doing business in the shadowy parking garage basements of the interwebs. Once he knocked on the right door and uttered the secret word, however, he became the proud owner of 50MHz additional bandwidth, decoders for SPI, I²C, and RS-232, twice the storage depth, and all teh triggers that ship with the 1104Z.

Can’t rationalize the purchase even at the ridiculously low price point? Here’s one way to make it happen. You’ll laugh, you’ll cry, you’ll learn some French.

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RFToy Makes Wireless Projects Easier

November 10, 2014 by Adam Fabio 7 Comments

[Ray] has created RFToy, a simple gadget to aid in setting up wireless systems with a variety of common radio modules. RFToy is an open source microcontroller board running on an ATmega328. While RFToy is Arduino code compatible, [Ray] chose to ditch the familiar Arduino shield layout for one that makes it easier to install RF modules, and is more handheld friendly.

[RFToy] includes headers for the popular nRF24L01 2.4 GHz transceiver, as well as 433/315 transmitters and receivers found in many low-cost wireless electronic devices. The 128×64 pixel OLED screen and 3 button interface make it easy to set up simple user interfaces for testing new designs.

[Ray] hasn’t broken any new ground here. What he has done is create a simple tool for wireless projects. Anyone who’s worked on a wireless system can tell you that tools like this are invaluable for debugging why your circuit isn’t talking. Is it the transmitter? The receiver? Something else in the power supply circuit?

Check out [Ray’s] demo video after the break. In it, he sniffs, records, and plays back signals from several remote-controlled outlets. [Ray] also has a great demo of sending temperature data back and forth using an nRF24L01.

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Light Up Component Bins And A Manual Pick And Place

November 5, 2014 by Brian Benchoff 28 Comments

[Mike] makes some very niche musical instruments, and the production volume he’s looking at means there isn’t a need to farm out his assembly. This means doing everything by hand, including the annoying task of picking resistors and other components out of bins. After searching for a way to speed up his assembly process, he came up with the Stuffomatic, a device that locates the correct component at the press of a button.

The normal way of grabbing a part when assembling is reading the reference on the board, cross referencing the value on the BOM, and digging the correct part out of the bin. To speed this up, [Mike] put LEDs in each of the part bins, connected to a Teensy 2.0 that has the BOM stored in memory. Clicking a foot switch looks up the next component and lights up the LED in the associated part bin.

[Mike] says this invention has speeded up his assembly time by about 30%, a significant amount if you’re looking at hours to assemble one unit.

If you’re wondering exactly what [Mike] is assembling, check this out. It’s heavily inspired by the Ondes Martenot, an electronic musical instrument that’s about as old as the theremin, but a million times cooler. Video sample below.

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Piezo Vacuum Pump For Lightweight Pick And Place

October 30, 2014 by Brian Benchoff 21 Comments

If you’re building a pick and place machine, or even just a vacuum pen, you’ll need some way to pick up tiny part. This means something that sucks, aquarium tubing, and everything that goes with that. A few months ago, [Wayne] found an interesting device called a Micro Blower that will blow small amounts of air from a small, lightweight device. A few modifications later, and he had a piezoelectric vacuum pump for picking up tiny parts.

The Micro Blower [Wayne] found is available on Mouser for about $45, but this device blows. To turn it into something that sucks, he would need to find a way to block up the input side of the pump so it could draw a vacuum. Eventually settling on mounting the blower inside a stack of foam board, [Wanye] glued on a 20 gauge needle and was able to suck up 0603 SMD parts.

The new piezoelectric sucker is extremely light, and the power draw is very reasonable: 18V and 20mA. This would be a great device to mount to a certain pick and place machine without having to run vacuum lines through the mechanics of a motion platform. Video below.

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Self Replicating Skateboard…. What?!?!?

October 26, 2014 by Rich Bremer 19 Comments

[Bart] and company over at Pumping Station One make a lot of skateboard decks. They wanted to build a CNC Router that was not only portable but had a size that was optimized for cutting skateboard decks. The project got a little out of hand and the CNC Router ended up also being a skateboard! As crazy as that sounds, the craziest part may be that they built it in just one night.

The project started off with some stock Shapeoko 2 parts. Achieving the deck-cutting size required shortening the X Axis and tripling the length of the Y Axis resulting in a 250 x 1200mm work envelope. The DC spindle used accepts ER16 collets and has a fully variable speed control. The stand alone selectable 24/48 volt power supply has a neat DIY handle to ease transportation. Even though the router itself has skateboard trucks, it also has a handle at the front so it’s easy to grab and drag behind you.

The guys that built this admit that, as a skateboard, it is kind of crappy. They do go on to mention that a 230lb dude was able to ride it without incident. As a project, however, they hit their goals on the head, ending up with an easily-transportable dedicated skateboard-deck-making CNC Router.

Mobile Soldering Workstation Sets Up Quickly, Lets You Get To Work

October 26, 2014 by Rich Bremer 15 Comments

Who here hasn’t put off soldering up a project because pulling out and setting up all your soldering gear is a pain? A lot of hobbyists don’t have a dedicated workbench for such activities and their gear may even be packed away somewhere inconvenient. [laxap] has come up with a solution using a plastic toolbox as a base for his Mobile Soldering Workstation.

[laxap] started with a regular off the shelf toolbox that has a lid and three drawers on the bottom. Although the Weller soldering iron base fit nicely in the bottom drawer, it did necessitate ditching the middle drawer for clearance. The compartmentalized top drawer is unmodified and holds parts and supplies in an orderly fashion.

Lifting up the lid of the box reveals a removable tray, which as intended, is a great spot to store tools such as a multimeter and wire strippers. The area under the removable tray is reserved for a power strip and power cord storage. A hole drilled in the side of the toolbox allows quick access to the power strip’s plug, a quick pull out and plug in is all that is necessary to get this workstation powered up.

That front flip up panel was made specifically for this project. Not only does it help keep the drawers from sliding open during transport, it also holds a lamp to aid in seeing what you’re doing! A bent aluminum strip acts as a latch to keep the panel in position.

It’s a pretty simple idea but it certainly gets the job done and makes soldering a whole bunch more convenient. If you like mobile workbenches, you may want to check out this all-wooden shelf style or one that features integrated solderless breadboards.